1. Field of the Invention
The invention relates to a microwave generator having two electrodes which are provided in a housing and are separated via a spark gap which breaks down when a high voltage is applied in order to emit microwaves.
The operation of a microwave generator such as this is based on the idea that a high-voltage source, for example a capacitor bank which is charged in parallel on the basis of the principle of the Marx impulse voltage circuit and is then connected in series, is short-circuited via a spark gap and is thus discharged. The short-circuit results in highly oscillating discharge or short-circuit currents with a steep flank, which contain a mixture of very high frequencies which are in general emitted via an antenna as microwave energy with a broadband spectrum that is dependent on the frequency mixture. This broadband microwave spectrum has such a high energy density that the radio traffic in the vicinity of a microwave generator such as this is at least adversely affected, and the input circuits of electronic circuits can be disturbed or even destroyed by resonance effects. As an alternative to the use of a Marx impulse voltage circuit, it is also possible to use a high-voltage generator that is operated by explosives and which, in comparison to conventional high-voltage generators, can provide a single high-voltage pulse with extremely high pulse energy.
The emission of the microwaves is based on a discharge-dependent resonance effect. The initiating electrodes between which the spark gap is formed have further associated resonating electrode or conductor structures in which the discharge current pulse which is produced on breakdown leads to powerful sudden oscillations whose frequency mixture is a resonant peak depending on the instantaneous electrically effective geometry of the resonator and/or the resonator structure.
2. Discussion of the Prior Art
A microwave generator of the type mentioned initially is known from DE 101 51 565 A1. This generator comprises a spark gap which is formed between a small electrode in the shape of a mushroom head, and a larger, club-like electrode. Furthermore, an outer conductor is provided, which surrounds the club-shaped electrode and is connected via an appropriate connecting structure to the electrode which is in the form of a mushroom head. This connecting structure can be shifted together with the electrode which is in the form of a mushroom head via a spindle mechanism in its axial position with respect to the stationary second electrode and the stationary conductor surrounding it, for tuning purposes. The housing of this generator is closed in the area in which the electrode spindle is passed out by means of a large-area, plug-like isolating closure cover, on which the hollow-cylindrical conductor is also arranged, and extends from this housing end to the resonator electrode, which engages, at a distance from it, at the side.
This generator configuration is very complex and requires a large number of separate components, particularly in the area of the housing closure for the high-voltage supply, which is applied to the electrode spindle, where a specially designed closure cover composed of an adequate dielectric material must be provided, and on which the hollow-cylindrical conductor can also be mounted as described, in addition to the guide spindle.